Tunable cavity resonators are electronic components that are useable as filters for radio frequency electromagnetic signals, among other types of signals. In particular, tunable cavity resonators using the evanescent mode cavity-based implementation are effective filters that are low-loss and widely tunable. Additionally, cavity resonators using the evanescent mode implementation typically offer a good balance between filter size, signal loss, spurious-free dynamic range, and tuning range.
Tunable cavity resonators typically include either a piezoelectric or an electrostatic microelectromechanical systems (“MEMS”) tuning device. Piezoelectrically-tuned cavity resonators typically yield excellent radio frequency filtering results. These types of tuning devices, however, are typically large, with a diameter of approximately twelve to thirteen millimeters, and have slow response speeds that are on the order of one millisecond or more. MEMS electrostatically-tuned cavity resonators also typically yield excellent radio frequency filtering results; however, the aggressive electromechanical designs of known devices suffer from a low unloaded quality factor (“Qu”) due to effects from the biasing network that is used to control the MEMS tuner. Accordingly, known tuning devices for cavity resonators exhibit a tradeoff between size, unloaded quality factor, frequency tuning, tuning speed, and complexity of assembly.
As a consequence, further developments based on one or more of the above-described limitations are desirable for tunable cavity resonators.